Hasil untuk "Oils, fats, and waxes"

Barima Money, Rayan Hassan Modather, David Abutu et al.

Geopolymers are promising alternatives to Portland cement due to their lower carbon footprint, superior mechanical strength, durability, and reduced shrinkage. However, inconsistent data and significant variations in experimental results highlight the uncertainty surrounding the reaction mechanisms of clay-based geopolymers (CBGs) in high-temperature oil wells. This review provides critical insights into these mechanisms and summarizes CBG synthesis methods. It explores the reaction processes of CBGs under high-temperature oil well conditions and analyzes the variables influencing these mechanisms. This review also examines the application of CBGs in oil wells, focusing on the challenges and potential solutions. Laboratory studies show that Portland cement degrades at temperatures above 300 °F (150 °C), while CBGs maintain their integrity and strength at temperatures up to 1500 °F (815 °C). This makes them particularly suitable for high-temperature geothermal wells and high-pressure, high-temperature oil well cementing. The dominant reaction mechanisms of CBGs include chemical reactivity, dissolution, gelation, polymerization, and growth. These findings highlight the potential of CBGs in addressing the challenges of high-temperature oil wells, thereby paving the way for further research in this area.

Hichem Horra, Ahmed Hadjadj, Elfakeur Abidi Saad et al.

Abstract This study aims to investigate the limitations of geostatistical prediction models outside the observed data range for estimating rock strength in nonreservoir formations in large geological fields with limited wireline data. To address this gap, this method explores alternative approaches to estimate rock strength using minimum data. A novel 3D rock strength prediction model that integrates geostatistic with deep learning algorithms is proposed. Initially, the deep learning model is trained using the available dataset to capture the complex nonlinear relationships within the data. The developed model is used to increase the dataset size by focusing on nearby data points to mitigate geological variability. geostatistic methods are then applied to establish spatial correlations of rock strength across an extended range compared with those of the actual dataset. The results reveal marked improvements in both the prediction range and spatial resolution of rock strength through the proposed methodology. The developed deep learning models achieved coefficient of determination values ranging from 0.9 to 0.99, demonstrating excellent predictive capability. Cross-validation confirms the model effectively captures local variations. The prediction range in the field expanded by 250% compared to the initial dataset, successfully addressing areas that previously exhibited flat readings when the model was applied to the initial data. This study advances petroleum industry knowledge by integrating deep learning and geostatistical methods to overcome rock strength prediction limitations in nonreservoir formations. The novel 3D model enhances the prediction range and spatial resolution, addresses data gaps and enables better decision-making for areas with limited wireline data.

杜舒梦1，李蕊1，杨巍1,2，刘元法1,2，叶展1,2 DU Shumeng1, LI Rui1, YANG Wei1,2, LIU Yuanfa1,2, YE Zhan1,2

旨在为居民ω3和ω6型多不饱和脂肪酸（PUFA）的平衡摄入提供指导，基于维持肠道屏障功能实现慢性代谢性疾病的预防，概述了结肠组织黏膜屏障的结构，总结了ω6和ω3型PUFA摄入对结肠黏膜屏障功能的影响，并综述了ω6与ω3型PUFA摄入比例对结肠黏膜屏障功能影响的研究进展。ω3型PUFA可增加肠道有益菌群的丰度、抑制促炎细胞因子的生成，从而调控肠道屏障功能；而ω6型PUFA的摄入会改变机体肠道微生物的种类与数量，影响肠道黏膜屏障功能的发挥；ω6与ω3型PUFA比例与结肠黏膜屏障的稳定性密切相关，脂肪组织中低ω6与ω3型PUFA比例在降低慢性病风险方面意义重大。未来还需进一步深入研究ω6和ω3型PUFA的摄入影响结肠黏膜屏障功能的作用机制，为脂肪酸平衡摄入的膳食指导和慢性代谢性疾病的预防提供更精确的理论参考。Aiming to provide guidance for a balanced intake of ω3 and ω6 polyunsaturated fatty acids (PUFA) in the population to achieve the prevention of chronic metabolic diseases based on the maintenance of intestinal barrier function, the structure of the mucosal barrier of colonic tissues was outlined, the roles of ω6 and ω3 PUFA intake on its function were summarised, and research progress on the influences of the ratio of ω6 PUFA to ω3 PUFA intake on the colonic mucosal barrier function were reviewed. ω3 PUFA can increase the abundance of beneficial intestinal flora and inhibit the production of pro-inflammatory cytokines, thus regulating the intestinal barrier function; whereas the intake of ω6 PUFA will change the species and number of gut microorganisms in the organism, thus affecting the performance of the intestinal mucosal barrier function. The ratio of ω6 PUFA to ω3 PUFA is closely related to the stability of the colonic mucosal barrier, and a low ratio of ω6 PUFA to ω3 PUFA in fat tissue is significant in reducing the risk of chronic diseases. In the future, further in-depth studies are needed to investigate the mechanism of action of ω6 and ω3 PUFA intake in affecting the colonic mucosal barrier function, so as to provide more precise theoretical references for the dietary guidance of balanced fatty acid intake and the prevention of chronic metabolic diseases.

Mingming Zhang, Jinglin Wen, Zhiming Xu et al.

Abstract Borehole instability in igneous rock formation has attracted more and more attention in recent ten years. In order to understand the mechanism of wellbore instability in igneous formation, a borehole stability model is established by applying the thermal, seepage and stress coupling model combined with a true triaxial rock strength criterion, which can reveal evolution of borehole collapse pressure with time. The effect of drilling cycle on borehole collapse pressure considering the coupling effects of temperature, seepage, and stress is quantitatively analyzed. Results show that, compared with only considering the effect of stress, wellbore collapse pressure increases with the coupling effect of temperature, seepage, and stress. Meanwhile, the stability of wellbore can be enhanced by reducing drilling fluid temperature; with the increase of formation porosity, the borehole collapse pressure increases rapidly, and then remains unchanged or decreases; while with the increase of formation permeability, borehole collapse pressure decreases rapidly, i.e. the shear failure of wellbore is mitigated. Besides, compared with vertical well, the horizontal well is more sensitive to the change of rock permeability. The investigation of drilling cycle shows that, the borehole collapse pressure increased sharply when the formation was drilled instantaneously. However, the subsequent growth trend slows down, which suggests that during the early stages of drilling operation, it is advisable to appropriately increase the mud weight to enhance the wellbore’s support capability by the bottomhole pressure. The research findings can enhance the understanding of the instability mechanism of igneous rock formations and reduce the risk of wellbore instability in igneous rock formations.

Ryzhkova S.V., Deshin A.A.

The results of one-dimensional modeling of oil and gas generation by organic matter of the non-oil and oil-bearing Bazhenov Formation in a well network within the northern part of Nyurol megadepression are presented. Modeling considering the mixed lithology of the Bazhenov Formation has no significant effect on the resource assessment, but refines the most important parameter of the hydrocarbon system, which is porosity. Based on the obtained data and taking into account the tectonic history, the history of liquid hydrocarbon generation has been reconstructed. The intensity of generation in different parts of the megadepression and adjacent structures depends on their spatial association with the zones of development of Triassic graben-rifts, as well as the relative growth of paleo-uplifts with the bending of the Western Siberian geosyncline. Recent tectonic movements have had a significant impact on the dynamics of oil generation.

Chuanxiang SUN, Haikuan NIE, Haikun SU et al.

To investigate the porosity, permeability and rock mechanics of deep shale under temperature-pressure coupling, we selected the core samples of deep shale from the Lower Silurian Longmaxi Formation in the Weirong and Yongchuan areas of the Sichuan Basin for porosity and permeability experiments and a triaxial compression and sound wave integration experiment at the maximum temperature and pressure of 120 °C and 70 MPa. The results show that the microscopic porosity and permeability change and the macroscopic rock deformation are mutually constrained, both showing the trend of steep and then gentle variation. At the maximum temperature and pressure, the porosity reduces by 34%–71%, and the permeability decreases by 85%–97%. With the rising temperature and pressure, deep shale undergoes plastic deformation in which organic pores and clay mineral pores are compressed and microfractures are closed, and elastic deformation in which brittle mineral pores and rock skeleton particles are compacted. Compared with previous experiments under high confining pressure and normal temperature, the experiment under high temperature and high pressure coupling reveals the effect of high temperature on stress sensitivity of porosity and permeability. High temperature can increase the plasticity of the rock, intensify the compression of pores due to high confining pressure, and induce thermal stress between the rock skeleton particles, allowing the reopening of shale bedding or the creation of new fractures along weak planes such as bedding, which inhibits the decrease of permeability with the increase of temperature and confining pressure. Compared with the triaxial mechanical experiment at normal temperature, the triaxial compression experiment at high temperature and high pressure demonstrates that the compressive strength and peak strain of deep shale increase significantly due to the coupling of temperature and pressure. The compressive strength is up to 435 MPa and the peak strain exceeds 2%, indicating that high temperature is not conducive to fracture initiation and expansion by increasing rock plasticity. Lithofacies and mineral composition have great impacts on the porosity, permeability and rock mechanics of deep shale. Shales with different lithologies are different in the difficulty and extent of brittle failure. The stress-strain characteristics of rocks under actual geological conditions are key support to the optimization of reservoir stimulation program.

Changliang JIANG

The development history and technical change of oil and gas pipeline quality management in China were reviewed focusing on pipeline quality control in the whole life cycle, on the basis of quality improvement of oil and gas pipelines in the construction period. Starting with the construction of the "8.3" pipeline, China's long-distance oil and gas pipeline construction has undergone four major stages of leap-forward development, forming a new pattern of oil and gas strategic channels "running north-south, crossing east-west, covering the whole country and connecting overseas". With the extensive application of automatic and intelligent technologies, the construction level and engineering quality of pipelines have been significantly improved. With the mature application of whole life cycle risk assessment, monitoring and inspection, integrity evaluation and other integrity management technologies, the operational risks of pipelines have been effectively controlled. With the improvement of welding technology and construction quality, the promotion and application of digital technology, the improvement of the whole life cycle integrity technology system, and the breakthrough in the failure mechanism of high-grade steel pipelines, the intrinsic safety and the quality and safety management level of oil and gas pipeline in the whole life cycle have been effectively improved. Besides, analysis was conducted on the challenges faced by the construction quality and operation safety of oil and gas pipelines. In addition, the logical relationship of mutual undertaking and support between quality, risk and safety of pipelines in the whole life cycle was discussed, by considering the key quality control factors, such as the causes of girth weld defects, full-automatic welding and performance improvement. Moreover, the essential relationship among quality control, risk identification and safety management was analyzed based on the construction and operation practice of the China-Russia Eastern Gas Pipeline. Then, a new construction quality and operation safety model with "quality control as the basis, total-factor management as the core and enhanced whole life cycle risk resistance" was put forward. Finally, the technical direction of quality control and safety management of oil and gas pipelines was prospected based on the application of "Industrial Internet +" and digital technology.

杨国龙，徐倩，胡培泓，刘伟，孟鹏程 YANG Guolong, XU Qian, HU Peihong, LIU Wei, MENG Pengcheng

为解释蜂蜡基油凝胶持油性较好的原因，对蜂蜡基油凝胶中的晶型及结晶聚集体的结构层次进行研究。分别以高油酸葵花籽油和大豆油为原料油，蜂蜡为凝胶因子制备蜂蜡基高油酸葵花籽油油凝胶和蜂蜡基大豆油油凝胶，采用X-射线衍射和偏光显微分析技术分别研究了2种蜂蜡基油凝胶的晶型与微观形态。X-射线衍射分析结果表明，蜂蜡基油凝胶在2θ为21.3°和23.7°处有明显衍射峰；但在小角区域没有明显的衍射峰。偏光显微分析结果表明，在放大倍数为500倍时，可观察到单个的细小针状物或棒状物（初级颗粒）及其聚集体（簇），还有由3个或4个这样的聚集体形成的更大的聚集体群（簇群），其形状呈十字花瓣状或海胆状，据此提出了蜂蜡基油凝胶结晶聚集体的结构层次,即初级颗粒-簇-簇群-网络结构，这种网络结构使油凝胶结晶聚集体的结构紧凑、比表面积大、颗粒细小，能很好地束缚油凝胶中的液体油，使得蜂蜡基油凝胶表现出很好的持油性。 To explain the reason for better oil-holding properties of beeswax-based oleogels, the crystal form and structural hierarchy of crystal aggregates in beeswax-based oleogels were investigated. The beeswax-based high oleic sunflower seed oil and soybean oil oleogels were prepared using high oleic sunflower seed oil and soybean oil as the raw oil and beeswax as the gel factor, respectively.The crystal form and microscopic morphology of beeswax-based high oleic sunflower seed oil and soybean oil oleogels were studied by X-ray diffraction and polarized light microscopy(PLM), respectively. The results of X-ray diffraction showed that the beeswax-based oleogels presented two distinct peak at 2θ 21.3° and 23.7°， however there were no distinct peak in small angel region. The results of PLM indicated that at a magnification of 500, single fine needles or rods (primary particles) and their aggregates (clusters) could be observed, as well as larger aggregate of clusters (clusters) formed by three or four such aggregates with a crossed petal or sea urchin shape. According to the PLM, the structural hierarchy of the crystal aggregates in beeswax-based oleogels was proposed as primary particle-cluster-aggregate of clusters-network, and the network structure results in the compact structure of the crystal aggregates of the oleogels, large specific surface area and fine particles, which could well bind the liquid oil in the oleogels and make the beeswax-based oleogels exhibit good oil-holding properties.

Xingang Bu, Ming Han, Abdulkareem M. AlSofi

This work numerically investigates surfactant effects on spontaneous water imbibition in oil-wet carbonates. An open boundary core-scale imbibition model with 9 × 9 × 10 gridblocks was used in UTCHEM to simulate carbonate core plug exposure to a vast water body. The simulation models were developed based on surfactant-assisted imbibition tests that were conducted in secondary and tertiary oil production modes using Amott cells at 75°C. Capillary and gravity forces were captured by history matching the experiments. Through history matching, the inputs for surfactant adsorption and diffusion, capillary pressure and relative permeability were calibrated. In tertiary mode, the surfactants-assisted imbibition process presents the performance in mixed-wet state rather than oil-wet state, which is governed by wettability alteration. A simulation model for surfactant-assisted imbibition in secondary mode was used to investigate the effects of various factors including interfacial tension (IFT) reduction, wettability alteration, adsorption, volume of surrounding water and capillary force. The simulation results suggest that surfactant-assisted water imbibition in secondary mode is gravity dominant, which is facilitated by both IFT reduction and wettability alteration caused by addition of proper surfactants. Different from water imbibition in water-wet core, it presents vertically dominant oil flow with a hemispherical oil-rich area and uneven remaining oil saturation. It is obvious that sufficient surfactant supply in vast water is required to make effective imbibition, in consideration of surfactant consumption and changes in concentration gradients. This core-scale modeling provides insights of surfactant-assisted imbibition in initially oil-wet carbonates and helps scale up the application in a cost-effective way.

van der Beek Eline M., Oosting Annemarie

Worldwide, overweight and obesity have increased dramatically, not only in high income countries. Clearly, unhealthy diets and sedentary lifestyle are important drivers of the increased obesity rates, but increasing evidence indicates that the vulnerability for later life non-communicable diseases is set during the first 1000 days, the period from conception until 2 years of age. The growth during this period is faster than during any other period in life. Dietary fats provide energy for growth, but also supply essential fatty acid (FA) precursors for long chain polyunsaturated FA that are building blocks and signals for adipose tissue development. Both epidemiological and experimental data support the notion that specific improvements in dietary fat quality, e.g. specific changes in the fatty acid composition as well as the structural organization of dietary lipids, may reduce the risk of obesity and other adverse outcomes in later life, but clinical evidence is limited and largely inconclusive. We anticipate that effects of such relatively small improvements in nutrient quality may be difficult to measure on the short term and have limited impact in healthy children. However, for children that already experience challenging conditions in the womb and have a higher risk profile based on deviations in birthweight and postnatal growth, the potential protective effects of improved dietary lipid quality in early life could be more substantial. Results from randomized clinical studies testing improved lipid quality concepts will help to develop specific strategies to adapt infant nutrition based on the need with the aim to improve long term outcomes.

LIU Wentao, ZHANG Defu, CHENG Hongjie et al.

Polymer flooding is one of the important means in enhancing oil recovery. Based on the physical process of polymer flooding, the well test model of three parts composite reservoir composed of Newtonian fluid/non-Newtonian power-law fluid/Newtonian fluid was established. The Laplace transform was used to obtain the analytical solution. The analytical solution of Laplace space was inverted to the real space by using Stehfest numerical inversion algorithm, and the double logarithmic theoretical curves of well test analysis describing the seepage characteristics of polymer flooding process were obtained. According to the characteristic of the derivative curve, four typical flow stages can be identified: the pure well bore effect stage, radial flow stage of inner part, polymer part and outer part. In the radial flow stage of inner part, the double logarithmic curves of the pressure derivative is a horizontal line with the value of 0.5. The larger the radius is, the longer the horizontal line will be. In radial flow stage of polymer part, the double logarithmic curves of the pressure derivative is a line with the slope of （1-<i>n</i>）/（3-<i>n</i>）. The smaller the power law index is, the greater the slope of the derivative curve will be. In the radial flow stage of outer part, the double logarithmic curves of the pressure derivative is a horizontal line with the value of 0.5<i>M</i>₁₃. The model can be used to analyse the effect of polymer flooding and guide the effective interpretation of well test data in polymer flooding reservoirs.

Fengming JIN, Kaixun ZHANG, Quan WANG et al.

In order to reveal the development mechanism of high-quality clastic rock reservoir, the basic characteristics of Sha-3 Member of the Shahejie Formation in the Raoyang sag, Bohai Bay Basin, are analyzed based on cores observation, thin-sections and SEM images, and petrophysical properties measurements as well. It is found that high-mature composition and texture, early oil charging, and dissolution are the main factors controlling the formation and preservation of pores in deep reservoirs. Compaction is the major factor destructing pores, whereas formation overpressure is conducive to the preservation of original pores, high compositional and medium textural maturity can enhance the resistance capacity to compaction and protect primary pores. Early oil charging could lead to temporary cessation of diagenesis and thus inhibit the cementation. When organic acids entered reservoir formations, considerable amounts of secondary pores were formed, leading to the local improvement of petrophysical properties. When predicting good quality belt in exploration of deep basin, it is recommended that the superimposing effects of the multiple factors (overpressure, early oil charging, compositional and textural maturity, diagenesis) be taken into consideration. Key words: Bohai Bay Basin, Raoyang sag, rifted basin, Shahejie Formation, diagenesis, high porosity zone, dissolution

Tu Yadong, Xu Xiaobing, Yin Huafeng et al.

In view of the problem that the inner wall of the high-pressure manifold is damaged by erosion during the fracturing operation, the erosive wear rate and the erosion dispersion distribution of the inner wall of the high-pressure manifold are studied using FLUENT software based on the solid-liquid two-phase flow and the erosive wear theory. The influence of the bend curvature radius, bend curvature and the inner diameter of the high-pressure manifold on the erosive wear of the manifold were analyzed. The results show that the erosive wear is the most serious at the outlet of the bend of the high-pressure manifold. The discrete distribution is concentrated at the bend to the outlet of the straight pipe. The erosion wear rate in the straight pipe is very small. With the increase of the inner diameter, the curvature radius of the bend and the bend curvature, the maximum and the average erosion wear rate of the manifold decrease. With the increase of the inlet flow velocity, the maximum and the average erosion wear rate increases. The results can provide references for the failure, failure prevention and protection of high-pressure manifold.

Arshad Raza, Raoof Gholami, Reza Rezaee et al.

Depleted gas reservoirs are recognized as the most promising candidate for carbon dioxide storage. Primary gas production followed by injection of carbon dioxide after depletion is the strategy adopted for secondary gas recovery and storage practices. This strategy, however, depends on the injection strategy, reservoir characteristics and operational parameters. There have been many studies to-date discussing critical factors influencing the storage performance in depleted gas reservoirs while little attention was given to the effect of residual gas. In this paper, an attempt was made to highlight the importance of residual gas on the capacity, injectivity, reservoir pressurization, and trapping mechanisms of storage sites through the use of numerical simulation. The results obtained indicated that the storage performance is proportionally linked to the amount of residual gas in the medium and reservoirs with low residual fluids are a better choice for storage purposes. Therefore, it would be wise to perform the secondary recovery before storage in order to have the least amount of residual gas in the medium. Although the results of this study are useful to screen depleted gas reservoirs for the storage purpose, more studies are required to confirm the finding presented in this paper.

Lu WANG, Shenglai YANG, Yicheng LIU et al.

Abstract: The CT scan, mercury intrusion test and commingled production physical simulation experiment of pore-, cavity-, and fracture–cavity-type cores were conducted to study the effects of interlayer heterogeneity, drawdown pressure, water saturation and water invasion on gas supply capacity. The experimental results were verified by the radial numerical model of multilayer commingled production based on the Eclipse software. The experimental results show that: the fracture–cavity-type reservoir with strong seepage capability makes great contribution to gas production in the early stage, while the pore- and cavity-type reservoirs with weak seepage capability make more contribution to gas production in the middle and late stages; the absolute permeability of reservoir affects its contribution to productivity, while the relative permeability of reservoir affects the total recovery; the “dynamic supply balance” state among various reservoirs can be achieved under a reasonable drawdown pressure; although the gas production capacity of the fracture–cavity-type reservoir is less affected by edge and bottom water, water breakthrough will first occur in this type reservoir and block other reservoirs, significantly reducing the commingled gas supply capacity and recovery. Key words: fracture–cavity carbonates, micropore structure, high temperature and high pressure physical modeling, commingled production, gas supply capacity

Zhixin WEN, Zhaoming WANG, Chengpeng SONG et al.

Based on the plate tectonic theory, and by studying seismic, geologic data and related documents, this study restored the proto-type basins and lithofacies paleogeography of East African passive margin basins in the major geological periods, and carried out analysis on the basin architecture characteristics and sedimentary filling variance. Based on the dissection of fifteen reservoirs, three hydrocarbon accumulation models were identified to find out favorable plays and the further exploration direction in this region. The East African passive continental margin basins experienced three prototype stages, Late Carboniferous-Triassic Karoo intercontinental failed rifts, Jurassic intercontinental-intracontinental rifts, and passive continental margins since the Cretaceous. The rift sequences are developed in all the basins, forming the “rift type”, “rift depression type” and “delta reconstruction type” passive continental margin basins in line with the different thicknesses of the sediment fillings during the depression period. In the “rift type” basins, the sediment thickness during the depression period was less than 3 000 m, forming “single source – structure type” hydrocarbon accumulation model, where the exploration direction will mainly focus on giant structural traps on the top of the rift sequences. In the “fault-depression type” basins, the sediment thickness during the depression period was more than 5 000 m, forming “double sources – double combinations type” hydrocarbon accumulation model, where the exploration direction will mainly focus on giant slip-collapse-debris flow deposits on the top and middle of the slope. In the “delta-reconstruction type” sediment basins, the thickness is more than 6 000 m, forming constructional delta deposits with four structural belts from onshore to offshore, unique growth faults, mud diapirs, thrust faults and fore deep gentle slope, which are named as “three sources – multi-combinations type” hydrocarbon accumulation model, and all the four structural belts can form giant oil and gas fields. Key words: east Africa, passive continental margin basin, proto-type basin, lithofacies paleogeography, basin structural architecture, hydrocarbon accumulation model, deep-water sediment, petroleum exploration direction

Bonneau Xavier, Vandessel Pieter, Buabeng Maxwell et al.

A range of various different planting distances (from 7.5 to 9.5 m) between oil palms were tested using an equilateral triangle design in a plantation density experiment which was settled in an oil palm commercial plantation in Nigeria. Climatic conditions were quite stable, with two seasons and around 2000 mm of annual rainfall. The soil was of desaturated ferralitic type, sandy on the surface, deep and without coarse elements. The early impact of plantation density was analysed at eight years after planting. Some early signs of depressive effect on yields were found for high planting densities (180 and 205 p/ha). Such a negative impact was not severe enough to counteract the effects of a higher number of palms per hectare. As a consequence, a gradient could be observed as yields (in tons of bunches per hectare) increased with density. We can anticipate that the competition effect between palms will increase over time with high densities, so that the counteracting point ought to be reached in a few years. A thinning treatment has been included in the protocol. Thinning was carried out at the end of the eight-year period.